IRON Mastering Compressor – Studio Magazin

"German manufacturer SPL has just raised the bar when it comes to mastering compressors."

German periodical Studio Magazin has just put out the first-ever review of our IRON Mastering compressor. In the current issue (09/2015), Fritz Fey and Friedemann Kootz decided to put the IRON to the test and write a comprehensive review. Below you can find some of their impressions, but the full review (in German) is certainly worth a read (you can download it from our server). Right from the very first words you can tell how everything is going to unfold:

"A conceptual masterpiece conceived by SPL Chief Developer and company owner Wolfgang Neumann."

The IRON compressor is utterly convincing, regardless of the application.

"I know of no other unit in this category that is so versatile and self-contained."

"The compressor is completely transparent even with a 7dB gain reduction. To hear how flagrant the difference is you simply need to switch to the uncompressed signal. It's unbelievable…“ (Rectifier: LED, Bias: Low, Side-Chain: Off, Attack/Release at 12 o'clock)

"With very high levels sound becomes thicker and more prominent, but never sloppy, with an elegant or soft THD."

"Germanium is a bit more aggressive and requires longer time-constant settings. However, once you have found the right setting, both germanium and silicon are as clear as a Fairchild with nice breath sounds, as soon as you push it or toggle Tube Bias to High.“

"I obviously ran it hard, too, with Tube Bias set to High and the VU-meters to the limit. And surprisingly, the signal is still useful, for example for parallel compression on drums ...“ (Rectifier: Germanium/Silicon)

"Thanks to the 120-volt technique it's almost impossible to overdrive this unit."

"I wouldn't shy to say that this piece of gear is downright impressive and, in my opinion, a true beauty that will make your 19" rack more sexy."

"Once you've used it you don't want to let go."

There's only one thing left unanswered:

In what color would you like yours?

Red or black? ;-)

For more information, images and videos of the IRON visit

And feel free to download the full review (in German) from our server.